Performance dress sock

ABSTRACT

A sock having a low pressure area made of a first knit density and at least one high pressure area made of a variable knit density portion. The variable knit density has portions that are made of a second knit density greater than the first knit density. The at least one variable knit density portion is arranged transverse to an orientation of major strain. A sock may also have hydrophobic fibers located substantially across a surface of the sock adapted to be adjacent to skin when worn and hydrophilic fibers located substantially across the hydrophobic fibers and extending therefrom to form loop structures adapted for wicking moisture away from the hydrophobic fibers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/791,208, filed on Mar. 15, 2013, which is incorporated herein byreference as if set forth in its entirety.

FIELD OF THE INVENTION

This invention relates generally to performance apparel and,particularly, to performance dress socks.

BACKGROUND

Socks pose a particularly difficult problem with respect to performanceas they experience significant strain during walking due to movement ofthe foot throughout a gait cycle. Further, stresses in socks areamplified as a significant portion of a wearer's weight is placed oneach foot while walking Often, compromises are made to provide either asock that is durable but inappropriate for office wear (e.g., athleticsocks) or a sock that is designed for appearance and wear with officeattire (e.g., dress socks) that tends not to be as durable. Also, manysocks are manufactured with a substantially constant knit density, whichtends to provide either cushioning (in the case of a higher knitdensity) or dynamic stretch properties (in the case of a lower knitdensity). Therefore, there is a need for durable, comfortable socks thatare considered appropriate for wear in professional environments, andthat also provide a combination of cushioning and dynamic stretchabilities.

SUMMARY OF THE INVENTION

Embodiments of a performance dress sock incorporate select materials andconstruction to improve wearer comfort and durability of the wares whilemaintaining a professional appearance (e.g., in an office setting). Theperformance dress sock can have a half-calf or mid-calf arrangement withthe upper part of the sock largely driven by aesthetic considerations,as opposed to typical socks which maintain a relatively

In one aspect, the invention relates to a sock having a low pressurearea made of a first knit density and at least one high pressure areamade of a variable knit density portion. The variable knit density hasportions that are made of a second knit density greater than the firstknit density. The at least one variable knit density portion is arrangedtransverse to an orientation of major strain.

In one embodiment of the above aspect, the variable density portion islocated in a portion corresponding to a metatarsal region of a foot whenthe sock is worn. The variable density portion may be arrangedtransverse to a line connecting a first metatarsophalangeal joint regionto a fifth metatarsophalangeal joint region. The variable densityportion may be a pattern. The pattern may be a plurality of polygons,and the pattern may be a grid. In some embodiments, the sock has africtional surface adapted to be aligned along an orientation of minorstrain. The frictional surface may be located in a rear portion of thesock, and the frictional surface may be one or more strips. In certainembodiments, the frictional surface is made of at least one of urethaneand silicone.

In some embodiments, the sock has a third knit density portion (with aknit density greater than the first knit density) near an areacorresponding to an arch of a foot when the sock is worn. The third knitdensity portion may extend around the sock to surround the arch areawhen the sock is worn. In certain embodiments, the sock is a dress sock.The sock may be made of synthetic polyester comprising activatedcharcoal, such as coffee grounds.

In another aspect, the invention relates to a sock having hydrophobicfibers located substantially across a surface of the sock adapted to beadjacent to skin when the sock is worn. The sock also has hydrophilicfibers located substantially across the hydrophobic fibers and extendingtherefrom to form loop structures adapted for wicking moisture away fromthe hydrophobic fibers.

In one embodiment, the sock has a greater amount of hydrophilic fibersthan hydrophobic fibers. The sock may have about a 75/25 ratio ofhydrophilic fibers to hydrophobic fibers.

In another aspect, the invention relates to a method of manufacturing aperformance dress sock. The method includes the steps of roboticallyknitting a low pressure area of the sock at a first knit density androbotically knitting a high pressure area of the sock at a variable knitdensity. The variable knit density has portions having a second knitdensity greater the first knit density. The at least one variable knitdensity portion is arranged transverse to an orientation of majorstrain.

BRIEF DESCRIPTION OF THE FIGURES

Other features and advantages of the present invention, as well as theinvention itself, can be more fully understood from the followingdescription of the various embodiments, when read together with theaccompanying drawings, in which:

FIG. 1A is a depiction of a strain profile obtained throughexperimentation with orientations of strain and an outline of a footsuperimposed thereon;

FIG. 1B is a schematic bottom view of a sock designed taking intoconsideration the strain profile of FIG. 1A and the pressure profile ofFIG. 2, in accordance with one embodiment of the invention;

FIG. 2 is a depiction of a pressure profile obtained throughexperimentation with an outline of a foot superimposed thereon;

FIG. 3 is a schematic, side, cross-sectional view of the sock of FIG. 1with arrows indicating thermal escape paths, in accordance with oneembodiment of the invention;

FIG. 4 is a schematic depiction of one arrangement of hydrophobic andhydrophilic fibers in relation to a skin surface, in accordance with oneembodiment of the invention;

FIG. 5A is a schematic depiction of polyester fiber infused with coffeecharcoal and a structure of the coffee charcoal, in accordance with oneembodiment of the invention;

FIG. 5B is a magnified view of the polyester fiber infused with coffeecharcoal of FIG. 5A;

FIG. 5C is a magnified view of the structure of the coffee charcoal ofFIG. 5A;

FIG. 6A is an isometric view of loafer socks, in accordance with oneembodiment of the invention;

FIG. 6B is a schematic, isometric view of the loafers socks of FIG. 6Awith a frictional surface;

FIG. 7A is an isometric view of a performance dress sock, in accordancewith one embodiment of the invention; and

FIG. 7B is a partial bottom view of the sock of FIG. 7A.

DETAILED DESCRIPTION

A performance dress sock may have several features that contribute toits performance and functioning as a second skin, beginning with anunderstanding of how the strain, pressure, and temperature of the footaffect various regions of the sock, as determined through body mapping.These analyses are described in detail below with respect to creating adress sock that provides cushioning venting, and dynamic stretchproperties in desired locations.

To understand skin strain dynamics on the medial, posterior, and plantarsurfaces of the foot, such as where soft tissue needs support (e.g.,through tension) and where skin is stretching the most, the GOM ARAMISOptical measurement system (Braunschweig, Germany) with stereohigh-speed video cameras was used to create a digital image correlationof a stochastic pattern. Six subjects with varying foot types weremonitored for deformation of the foot during the walking gait cycle,with the subjects both bare foot and wearing a shoe sawn in half tounderstand dynamics within the shoe. Plantar strain was monitored via anoptical arrangement through a transparent force plate. An exemplaryresult 100 (including superimposed lines 102 depicting the direction ofmajor strain and a foot outline 104) is depicted in FIG. 1A. Based onthis testing, it was determined that during midstance the arch of thefoot collapses, causing major strain in a transverse direction acrossthe arch, as depicted with the transverse arch line 106. In themetatarsal region, the orientation of major strain is angled from thefirst metatarsophalangeal joint (MPJ) to the fifth MPJ, as depicted withthe metatarsal strain line 108. In the Achilles heel region, majorstrain is oriented in a substantially vertical direction.

The performance dress sock is configured to address certain issuesidentified in the strain analysis, and to repeatably withstand wear andsupport a wearer throughout various movements. For example, as depictedin an embodiment of a performance sock 110 in FIG. 1B, a compressionband 112 a (e.g., an area of higher knit density) may be used in an areaof the sock 110 corresponding with the arch of the foot to provideadditional support. The compression band 112 a (e.g., the area of higherknit density) can apply greater tension along the direction of majorstrain than lower knit density areas, and can extend all the way aroundthe foot in the arch region. The compression band 112 a may also have ahigher elastane content (e.g., between about 20 and 40% by mass of theknit in the compression band 112 a) than other portions to support thearch. To reduce friction on the plantar surface (i.e., the sole of thefoot), and to reduce potential for blistering, the sock 110 may allowfor stretching along the direction/orientation of major strain in highpressure areas, as described in greater detail below. One way to achievethis selective stretchability is through a varied pattern (e.g., ofstripes or polygons) in relatively higher 114 a and lower knit density114 b (a variable density portion 116), which provides preference ofstretch in a certain direction (e.g., along a direction of major strainas determined by the strain analysis) while still providing cushioning.The variable knit density portion 116 covered by the pattern and/or thepattern itself may be arranged substantially transverse to thedirection/orientation of major strain to better maintain itscharacteristics even while being stretched. By allowing the sock 110 tostretch with and in the same manner as a wearer's skin, the userexperiences less blistering and more comfort, while avoiding many of theproblems associated with traditional socks, such as bunching andsagging.

These variable knit density portions 116 and the associated pattern maybe manufactured through various techniques, including robotic knitting.The higher knit density portions 114 a (or “cushions”) may be formed onan elastic base, allowing them to move independently and with the skin.For example, the sock 110 may be made substantially of a base layerhaving a lower knit density (e.g., a mass ratio of approximately 80%elastane to approximately 20% hydrophobic fibers) throughout, creating asock with good ventilation and stretching properties. To increasesupport, tension, and cushioning in certain areas (such as those areasdetermined by body mapping), additional fibers (particularly hydrophilicand/or hydrophobic fibers) may be added to increase the density andcreate a ratio of approximately 20% elastane, 40% hydrophobic fibers,and 40% hydrophilic materials. These are only exemplary ratios, andothers are contemplated, including for lower density vented areas to bemade with 100% elastane and for higher density areas to be made ofapproximately 80% hydrophilic material (e.g., cotton) and 20% elastane.Additionally, instead of forming a base layer and adding to it to createhigher density areas, higher density and lower density areas may beformed separately through the manufacturing process (e.g., throughrobotic knitting). The use and arrangement of hydrophobic andhydrophilic materials is described in greater detail below.

The performance dress sock is also designed to address issues associatedwith the pressure profiles developed during pressure mapping, which alsoimpacts the comfort and wear of the sock during walking To understandthe pressure profiles and the correlation between stress and strain, andwhere feet need the most cushioning, six subjects were monitored using aTekscan mat (South Boston, Mass.). An exemplary pressure profile 200 isdepicted in FIG. 2. The pressure profile 200 illustrates that pressureis highest in the metatarsal region 202 and the calcaneal region 204,with some pressure beneath the hallux 206. The areas with high stress(or pressure) and strain are expected to experience higher frictionwhile walking, which could very likely develop into blisters on the feetof the wearer. However, by designing a performance dress sock to allowstretching in these high pressure regions as described above (e.g., withvariable knit density areas 116 and/or high knit density areas 112 b,112 c), the risk of blisters can be greatly reduced. To preserve some ofthe breathability that may be lost in the high pressure regions whenusing high density knit cushions 114 a (which may provide cushioning andincrease comfort and overall durability), areas with minimal pressurecan have a lower knit density, such as on the upper side of the sock110.

While stress and strain are important considerations in the design ofthe sock 110 to make it feel like a second skin, it is also important toconsider the thermal effects on the wearer of such a sock. Thermalimaging may be used to identify the areas of the foot that experiencethe highest temperature during wear (called “hot spots”), and thus theareas that need the most ventilation. Temperature buildup may bealleviated at these hot spots by providing a path for the heat to escapeoutside of the sock 110, as depicted in FIG. 3. When the cushions 114 aand the lower density portions 114 b are arranged in a pattern, excessheat may more easily escape a foot through the lower density portions114 b, even when the sock 110 is under compression. Because of thedifference in thickness between the cushions 114 a and the lower densityportions 114 b, channels are formed between the cushions 114 a to allowthis escape. Balancing these temperature considerations with the strainand pressure considerations can lead to a much better performing andmore comfortable dress sock for a wearer.

In addition to allowing for the removal of heat, the sock 110 may alsobe designed to remove moisture from a wearer's foot. When moisturebuilds up and remains against a wearer's foot, the wearer can experiencean uncomfortable, clammy feeling. This feeling may remain evenimmediately after the moisture is removed, so it is desirable to providea mechanism for removing moisture on an ongoing basis. Blends ofhydrophobic and hydrophilic yarns (e.g., the hydrophobic syntheticpolyester and the hydrophilic cotton described above) can provide highermoisture transport rates from a skin surface than a layer made of 100%hydrophobic fibers. Various ratios between the amounts of hydrophobicand the hydrophilic materials may be used, including a 60/40, a 75/25,an 80/20, and other mass ratios between and beyond these values. Asarranged in FIG. 3, hydrophilic fibers 320 a can work to pull moistureaway from the skin surface 322, while hydrophobic fibers 320 b spreadmoisture horizontally across a surface, thereby increasing surface areaand accelerating evaporation of the moisture. The hydrophilic fibers 320a and/or the hydrophobic fibers 320 b may be untreated, relying onintrinsic known material properties to provide the desired wicking andevaporation. One embodiment of a joint hydrophilic/hydrophobicarrangement is depicted in FIG. 4. Such a construction may be found in ahigher knit density area 114 a, for which FIG. 4 would provide arepresentative schematic cross-sectional view. The hydrophobic fibers320 b are close to the skin, distributing moisture from certain areasacross a much larger surface area of the foot. The hydrophilic fibers320 a extend away from the hydrophobic fibers 320 b, forming“reservoirs” (or loops) in which moisture may accumulate followingwicking from the skin 322 and the hydrophobic fibers 320 b. The loopsmay be formed individually, allowing each to act as a separatereservoir, and a length of fiber forming each loop may be exposed to theenvironment (as opposed to trapping moisture within a layer of fabricand relying on pores for moisture to escape). The hydrophilic fibers 320a may be woven through a base layer closest to the skin (e.g., a layermade of elastane and/or particular hydrophobic fibers) in a variety ofdensities, including, for example, 100 loops per square inch. In certainembodiments, additional hydrophobic fibers 320 b may be included withthe hydrophilic fibers 320 a and woven together. The arrangement ofhydrophilic fibers 320 a looping away from the hydrophobic fibers 320 bremoves moisture from the skin 322 and provides a preferential wickingdirection toward the exterior of the sock 110, allowing the wearer tofeel dry even while moisture cannot be immediately removed from theenvironment (e.g., when wearing shoes). In this manner, the performancedress sock can provide high performance characteristics through moisturemanagement and comfort not experienced with other dress socks.

A wearer's experience may further be improved based on the materialsused, as fabric composition is a factor in both comfort and durability.The performance dress sock can include a combination of synthetic andnatural products, such as a combination of synthetic polyester andlong-staple cotton. Various compositions are contemplated, including anapproximately 60% synthetic polyester and an approximately 40%long-staple cotton composition. The synthetic polyester can containactivated charcoal, such as that may be created through the partialcombustion of used coffee grounds, as depicted in FIG. 5A. The carbonmatter (coffee charcoal) 530 may be blended into the polyester 532 priorto extrusion or otherwise infused into strands of polyester 532. FIG. 5Aalso depicts schematically how the activated coffee charcoal 530attracts and absorbs aromatic organic compounds and phenols 534 thatcommonly cause odor. FIGS. 5B depicts a greatly magnified view of thecoffee charcoal 530 blended with the polyester 532, illustrating how thecoffee 530 may be embedded within the polyester 532 but still exposed tothe environment. FIG. 5C depicts a greatly magnified view of the coffeecharcoal 530 with sponge-like pores 536 for absorbing the odor causingparticles 534. Such a composition has proven to be up to three timesmore effective at absorbing odor as compared to regular cotton, and upover twice as effective as polyester, based on test results using ASTMStandard D 5742. While the coffee charcoal 530 absorbs odor particles534 during wear, the odor particles 534 may be released when the socks110 are laundered, allowing for further odor capture when worn again.The materials used in the blend may come from many sources, includingrecycled sources for polyester and coffee previously ground at coffeeroasters and similar shops. The coffee 530 may be pharmaceuticallyprocessed prior to use in the blend to remove coffee oils tosubstantially remove its own scent.

FIG. 6A depicts an embodiment of the invention directed to a sock 610 ina loafer configuration. The sock 610 is largely similar to the sock 110,including a higher knit density in a metatarsal region 612 b and a soleregion 612 c, a variable knit density portion 616, and a lesser knitdensity on a top portion 630. One difference between the sock 610 andthe sock 110 is the absence of a compression band in the mid-section ofthe foot, though this may be included. Additionally, frictional surfaces632 may be applied to help prevent slipping of the sock 610 on the foot,as depicted in FIG. 6B. For example, the rear portion of loafer socks610 tend to slip below the foot when the sock 610 is stretched. Byproviding frictional surfaces 632 (e.g., printed strips of urethane orsilicone) along the transverse lines of non-extension or minor strainalong an interior heel region of the sock 610, friction can be increasedin contact areas while the fabric can stretch with the skin. Typically,in traditional construction, if a frictional surface is on the rear of asock (which often is not the case), it is applied over a relativelylarge, continuous surface area. This traditional frictional surface areatends to suffer from some of the same stretching issues as other areasof traditional socks, particularly down the foot in the direction ofmajor strain at the Achilles heel. Over time, the singular large surfacearea tends to migrate down the foot. Using separate spaced strips 632,as depicted in FIG. 6B, allows for the sock 610 to stretch in betweenthe strips 632 and does not substantially stretch the strips 632themselves, such that the strips 632 remain connected to the same areaof skin for the duration of wearing. This provides a consistent wearexperience without the need for constant adjustments, which isparticularly useful for loafers socks 610 that are cut very low so as tobe non-visible when worn with loafer shoes. A low friction fabric may beused at or near the top of the loafer sock to reduce irritation.

FIGS. 7A and 7B depict a performance dress sock 710 incorporating manyof the elements described above. For example, the sock 710 has areas ofrelatively low knit density (e.g., approximately 100 GSM) on top(dorsal) portions 730, separated by a compression band 712 a of higherknit density (e.g., approximately 200 GSM +/−15 GSM) to provide archsupport. The top portions 730 are not expected to experience significantchanges in pressure, so use of the light vented knit may be appropriate.Other areas that are not expected to experience changes in pressure mayhave the same or a similar light vented knit. In contrast, areasexperiencing the greatest pressure changes, (e.g., the metatarsal andsole regions 712 b, 712 c) may have higher knit densities to increasedurability. An upper part 732 of the sock 710 (i.e., the part thatsurrounds the calf) may have a substantially uniform medium knit density(e.g., approximately 150 GSM) to give a professional appearance, and mayinclude a flat seam at the top to reduce irritation. An interior of theupper part 732 of the sock may also have friction surfaces (e.g.,urethane strips or dots) to help prevent the socks from falling down theleg during wear. The plantar surface of the sock 710 depicted in FIG. 7Bmay have a padded surface 716 to provide cushioning in high pressureregions. In some embodiments, the padded surface 716 may be a grid,featuring an alternating pattern of thicker, higher knit densityportions 714 a (e.g., terry knitting), and lower density knit portions714 b. The small channels formed in such an arrangement facilitate vaportransfer even when the sock 710 is compressed against a sole of a shoe,as the variance in thickness between the higher knit density portions714 a and the lower knit density portions 714 b is adapted to create anoffset in thickness.

While the principles laid out above have been described with respect toa performance dress sock, it is easily understood that such a designprocess is easily applicable to other apparel, particularly apparel thattouches a wearer's skin. For example, it is contemplated that shirts andunderwear may be developed in the same manner as the socks describedherein, e.g., by understanding the strain and pressure profiles in theareas of the body associated with the skin contacting garment andcreating a design that allows for stretching with the skin of the wearerto provide comfort. This may be achieved by varying knit density acrossdifferent portions of the garment, as described herein with respect tosocks.

Various embodiments and features of the present invention have beendescribed in detail with particularity. The utilities thereof can beappreciated by those skilled in the art. It should be emphasized thatthe above-described embodiments of the present invention merely describecertain examples implementing the invention, including the best mode, inorder to set forth a clear understanding of the principles of theinvention. Numerous changes, variations, and modifications can be madeto the embodiments described herein and the underlying concepts, withoutdeparting from the spirit and scope of the principles of the invention.All such variations and modifications are intended to be included withinthe scope of the present invention, as set forth herein. The scope ofthe present invention is to be defined by the claims and allequivalents, rather than limited by the forgoing description of variouspreferred and alternative embodiments.

What is claimed is:
 1. A sock comprising: a low pressure area comprisinga first knit density; and at least one high pressure area comprising avariable knit density portion, the variable knit density comprisingportions having a second knit density greater than the first knitdensity, wherein the at least one variable knit density portion isarranged transverse to an orientation of major strain.
 2. The sock ofclaim 1, wherein the at least one variable density portion is disposedin a portion corresponding to a metatarsal region of a foot when worn.3. The sock of claim 2, wherein the variable density portion is arrangedtransverse to a line connecting a first metatarsophalangeal joint regionto a fifth metatarsophalangeal joint region.
 4. The sock of claim 1,wherein the variable density portion comprises a pattern.
 5. The sock ofclaim 4, wherein the pattern comprises a plurality of polygons.
 6. Thesock of claim 1 further comprising a frictional surface adapted to bealigned along an orientation of minor strain.
 7. The sock of claim 6,wherein the frictional surface is disposed in a rear portion of thesock.
 8. The sock of claim 6, wherein the frictional surface comprises aplurality of strips.
 9. The sock of claim 6, wherein the frictionalsurface comprises at least one of urethane and silicone.
 10. The sock ofclaim 1 further comprising a third knit density portion disposedproximate an area corresponding to an arch of a foot when worn, whereinthe third knit density is greater than the first knit density.
 11. Thesock of claim 10, wherein the third knit density portion extends aroundthe sock and is configured to surround the arch area when the sock isworn.
 12. The sock of claim 1, wherein the sock comprises a dress sock.13. The sock of claim 1 further comprising synthetic polyestercomprising activated charcoal.
 14. The sock of claim 13, wherein theactivated charcoal comprises coffee grounds.
 15. A sock comprising:hydrophobic fibers disposed substantially across a surface of the sockadapted to be adjacent to skin when worn; and hydrophilic fibersdisposed substantially across the hydrophobic fibers and extendingtherefrom to form loop structures adapted for wicking moisture away fromthe hydrophobic fibers.
 16. The sock of claim 15, wherein the sockcomprises a greater amount of hydrophilic fibers than hydrophobicfibers.
 17. The sock of claim 16, wherein the sock comprises about a75/25 ratio of hydrophilic fibers to hydrophobic fibers.
 18. A method ofmanufacturing a performance dress sock, the method comprising the stepsof: robotically knitting a low pressure area of the sock at a first knitdensity; and robotically knitting a high pressure area of the sock at avariable knit density, wherein the variable knit density comprisesportions having a second knit density greater the first knit density,and wherein the at least one variable knit density portion is arrangedtransverse to an orientation of major strain.